1. Field of the Invention
The present invention relates to a side airbag device in which an airbag is inflated for deployment at a side of an occupant.
2. Related Art
In general, side airbag devices are such as to protect the head, chest or waist of the occupant by relaxing an impact that is to be applied to the occupant by causing an airbag to be inflated for deployment at a side of the occupant when an impact of a predetermined value or greater is applied to a body side portion of a vehicle. For example, in Japanese Patent Publication No. JP H08-40176A and International Publication No. WO 03/13914, side airbag devices are disclosed in which an airbag is inflated for deployment at a side of an occupant seated in a rear seat. These side airbag devices are such as to be provided in a cover portion provided between the body side portion and a side of the rear seat. Then, in these side airbag devices, when an impact of a predetermined value or greater is applied to the body side portion of the vehicle, an opening is formed by, for example, breaking part of the cover so that the airbag is inflated for deployment from the opening so formed.
Incidentally, in the rear side airbag devices, the airbag has to be inflated for deployment from the accommodated space through a narrow opening space between the body side portion (door trim) and the rear seat. In addition, a cover is provided between the body side portion and the rear seat for concealing the airbag accommodated in the accommodating space, and in order for the airbag to be inflated for deployment, part of the cover has to be broken. In a vehicle such as a passenger vehicle, however, a distance between the body side portion to the rear seat is very short when compared with that of a front seat such as a driver's seat and a front passenger's seat. By this configuration, when an impact is applied sideways to the body side portion of the vehicle, a door trim which constitutes part of the body side portion enters the compartment within a very short period of time. From these facts, in the rear seat side airbag devices, in order to increase the protection performance for an occupant, it is strongly demanded that the airbag has to be inflated for deployment in an ensured manner even in the event that the door trim enters the compartment.